The number of children living in severe poverty in the UK rose by more than 250,000 to 1.7 million in the four years before the recession, it was claimed today.

Save the Children is warning that the effects of the recession, which started in the second quarter of 2008 and according to official figures released today ended at the end of 2009, are likely to have exasperated the problem since then.

Its research found London to be the worst culprit for child poverty in the UK, accounting for around one fifth of all children living in poverty.

And the children's charity has warned the number could rise further, and in the run up to the general election has said it wants the next government to "take urgent action in the first 100 days after the election to end child poverty".

However, the government has said it has taken 500,000 children in the UK out of poverty since 1997 and has pledged to end it completely by 2020.

Fergus Drake, director of UK programmes for the charity, said: "It's shocking that at a time when the UK was experiencing unprecedented levels of wealth the number of children living in severe poverty - we're talking about children going without a winter coat, a bed and other day-to-day essentials - actually increased.

"Measures introduced by the government in the last two years have managed to prevent the numbers spiralling even higher but with unemployment expected to rise there is now a danger that severe child poverty will increase even further."

The charity said in its research that living in severe poverty means living on less than £12,220 a year - for a couple with one child. This amount leaves families around £113 a week short of what they need to cover food, electricity and gas, phones, other bills, clothes, washing, transport and healthcare, not to mention furnishings, activities for children and other essential items.

Save the Children said: "Children and their parents are missing out on everyday essentials such as food and clothing. They cannot afford things that most families take for granted, such as celebrating a birthday or having a short family holiday."

The report also found that the proportion of children living in severe poverty is fairly similar across the four countries of the UK. In 2007/08, 13 per cent of children in England were living in severe poverty, 15 per cent in Wales, ten per cent in Northern Ireland and nine per cent in Scotland.

The year-on-year trend shows that severe poverty has increased in England and Wales since 2004/05. There has been no change in the number of children living in severe poverty in Northern Ireland and Scotland.